How to make it

1. Stir onion, vinegar, garlic and brown sugar in a 5- to 6-quart. slow cooker to combine. Spread whole-grain mustard all over chicken. Place chicken, breast-side down in slow cooker. Cover; cook on low-heat setting 5 to 6 hours, until chicken is fork-tender. Remove chicken from slow cooker to a cutting board and let stand 5 minutes.

2. Pour braising liquid from slow-cooker through a fine sieve set over a 1-quart measure. Transfer onion solids from sieve and 1/2 cup of the braising liquid to large bowl. Add dressing ingredients to onion mixture and whisk to combine.

3. Using 2 forks, shred the chicken off the carcass in large pieces. Add to dressing in bowl and toss. Serve on toasted buns or rolls, topped with coleslaw, if desired.

In a hurry to prepare? You can do this with boneless chicken in a Dutch Oven in your oven on a low temperature. I make a very similar mustard based "South Carolina BBQ" and we love it. I am going to try this sauce next time.